Hvac-apu systems for battery electric vehicles

ABSTRACT

A HVAC-APU system is provided for a battery electric vehicle. The system includes, but is not limited to a refrigerant fluid. A power cycle loop section, a cabin heating cycle loop section, and a cabin refrigeration cycle loop section are in selective fluid communication with each other to advance the refrigerant fluid through the system. A compressor-expander train includes, but is not limited to a reversing compressor-expander and a high-pressure pump that are operably connected by a shaft. The high-pressure pump pressurizes the refrigerant fluid to form a high-pressure refrigerant fluid. An auxiliary fuel cell and combustion unit heats a heat transfer fluid. A heat exchanger transfers heat from the heated transfer fluid to the high-pressure refrigerant fluid to form a heated high-pressure refrigerant fluid. The reversing compressor-expander expands the heated high-pressure refrigerant fluid to rotate the shaft in a first direction to drive the high-pressure pump.

TECHNICAL FIELD

The technical field relates generally to heating, ventilation andair-conditioning (HVAC) and auxiliary power unit (APU) systems for usein vehicles, and more particularly relates to HVAC and APU systems foruse in battery electric vehicles.

BACKGROUND

Internal combustion engine powered vehicles have been commerciallymarketed for over a century and dominate the vehicle industry. Despitetheir widespread use, gasoline fueled internal combustion engines havebeen associated with a number of issues. First, due to the finite sizeand limited regional availability of fossil fuels, major pricefluctuations and a generally upward pricing trend in the cost ofgasoline are common, both of which can have an impact at the consumerlevel. Second, fossil fuel combustion has been associated withenvironmental problems, such as, for example, exhaust emissionsincluding concerns over emissions of carbon dioxide, a greenhouse gas,and a contributor to global warming. Accordingly, considerable efforthas been spent on finding alternative drive systems for use in bothpersonal and commercial vehicles.

Battery electric vehicles offer a promising alternative to vehicles thatuse internal combustion drive trains. A battery electric vehicle is atype of electric vehicle (EV) that uses chemical energy stored inrechargeable battery, e.g., rechargeable battery packs, to provideelectric power to an electric motor, instead of an internal combustionengine, for propulsion. However, there are two main issues with using abattery electric vehicle.

The two main issues are concerns about the drivable range before runningout of a battery charge, which is commonly referred to as range anxiety,and what to do if the battery packs do run out of energy. Typicaldrivable ranges for battery electric vehicles are about 70 miles.However, these ranges depend considerably upon the age of the batterypacks, the driving conditions and the driving habits of the driver.Moreover, many battery electric vehicles are unsuitable for towing dueto potential damage that can occur to the transmission if the vehicle istowed. In such cases, a battery electric vehicle that becomes strandedon a roadside may require the use of a flatbed truck to transport thebattery electric vehicle to the nearest available power outlet forrecharging the battery packs.

Concerns over range anxiety and what to do if the battery packs do runout of energy are further exacerbated when a battery electric vehicle isdriven in an environment that calls for on-demand heating and/or coolingwithin the passenger cabin to provide occupant comfort and/or safety.This is because the HVAC system for a battery electric vehicle typicallyoperates using electrical energy from the battery packs, and the energynecessary to keep the passenger cabin comfortable in relatively extremeconditions can be on par with the same energy requirements needed tomove the battery electric vehicle down the road.

For example, operating the heating mode of an HVAC system for a batteryelectric vehicle at 10° F. outside conditions can reduce the drivablerange of the battery electric vehicle from about 70 miles to about 35miles. Moreover, if the energy charge does run out of the battery packsand the battery electric vehicle is stranded on a roadside, there is noelectrical energy from the battery packs to operate the HVAC systemwhile the occupants wait to be transported to the nearest availablepower outlet for recharging the battery packs.

Accordingly, it is desirable to provide an HVAC system for a batteryelectric vehicle that is operational when the energy charge runs out ofthe battery packs. Moreover, it is desirable to provide a batteryelectric vehicle with extended range capability to reduce range anxiety.Also, it is desirable to provide a battery electric vehicle with betteroptions and less expense if the battery packs do run out of energy andthe vehicle needs to be transported to the nearest available poweroutlet for recharging the battery packs. Furthermore, other desirablefeatures and characteristics of the present invention will becomeapparent from the subsequent detailed description and the appendedclaims, taken in conjunction with the accompanying drawings and thisbackground.

SUMMARY

HVAC-APU systems for battery electric vehicles that have passengercabins are provided herein. In an exemplary embodiment, a HVAC-APUsystem comprises a refrigerant fluid. A power cycle loop section isconfigured to advance the refrigerant fluid. A cabin heating cycle loopsection is in selective fluid communication with the power cycle loopsection and is configured to advance the refrigerant fluid. A cabinrefrigeration cycle loop section is in selective fluid communicationwith the power cycle loop section and the cabin heating cycle loopsection and is configured to advance the refrigerant fluid with thepower cycle loop section and the cabin heating cycle loop section. Acompressor-expander train comprises a reversing compressor-expander, ahigh-pressure pump and a shaft that operably couples the reversingcompressor-expander with the high-pressure pump. The high-pressure pumpis disposed along the power cycle loop section and is configured topressurize the refrigerant fluid to form a high-pressure refrigerantfluid. An auxiliary fuel cell and combustion unit contains a heattransfer fluid and is configured to heat the heat transfer fluid to forma heated transfer fluid. A heat exchanger is disposed along the powercycle loop section to receive the high-pressure refrigerant fluid and isin fluid communication with the auxiliary fuel cell and combustion unitto receive the heated transfer fluid. The heat exchanger is configuredto transfer heat from the heated transfer fluid to the high-pressurerefrigerant fluid to form a heated high-pressure refrigerant fluid. Thereversing compressor-expander is in selective fluid communication withthe heat exchanger to receive the heated high-pressure refrigerant fluidand is configured to expand the heated high-pressure refrigerant fluidto rotate the shaft in a first direction to drive the high-pressurepump.

In accordance with another exemplary embodiment, a HVAC-APU system for abattery electric vehicle that has a passenger cabin is provided herein.The HVAC-APU system is configured to receive an auxiliary fuel cell andcombustion unit that contains a heat transfer fluid and which isoperable to heat the heat transfer fluid to form a heated transferfluid. The system comprises a refrigerant fluid. A power cycle loopsection, a cabin heating cycle loop section, and a cabin refrigerationcycle loop section are in selective fluid communication with each otherto advance the refrigerant fluid through the system to provide variousoperating modes. A compressor-expander train comprises a reversingcompressor-expander, a high-pressure pump and a shaft that operablycouples the reversing compressor-expander with the high-pressure pump.The high-pressure pump is disposed along the power cycle loop sectionand is configured to pressurize the refrigerant fluid to form ahigh-pressure refrigerant fluid. A heat exchanger is disposed along thepower cycle loop section to receive the high-pressure refrigerant fluid.The heat exchanger is configured for fluid communication with theauxiliary fuel cell and combustion unit to receive the heated transferfluid and to transfer heat from the heated transfer fluid to thehigh-pressure refrigerant fluid to form a heated high-pressurerefrigerant fluid. The reversing compressor-expander is in selectivefluid communication with the heat exchanger to receive the heatedhigh-pressure refrigerant fluid and is configured to expand the heatedhigh-pressure refrigerant fluid to rotate the shaft in a first directionto drive the high-pressure pump.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will hereinafter be described inconjunction with the following drawing figures, wherein like numeralsdenote like elements, and wherein:

FIG. 1 is a schematic depiction of a HVAC-APU system for a batteryelectric vehicle in a heating mode in accordance with an exemplaryembodiment;

FIG. 2 is a schematic depiction of a HVAC-APU system for a batteryelectric vehicle in a refrigeration mode in accordance with an exemplaryembodiment;

FIG. 3 is a schematic depiction of a HVAC-APU system for a batteryelectric vehicle in a heating mode and a power generation mode inaccordance with an exemplary embodiment;

FIG. 4 is a schematic depiction of a HVAC-APU system for a batteryelectric vehicle in a refrigeration mode and a power generation mode inaccordance with an exemplary embodiment; and

FIG. 5 is a schematic depiction of a HVAC-APU system for a batteryelectric vehicle in a demisting mode and a power generation mode inaccordance with an exemplary embodiment.

DETAILED DESCRIPTION

The following Detailed Description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Furthermore, there is no intention to be bound by any theorypresented in the preceding Background or the following DetailedDescription.

Various embodiments contemplated herein relate to HVAC-APU systems for abattery electric vehicle. The system has a power cycle loop section, acabin heating cycle loop section, and a cabin refrigeration cycle loopsection that are in selective fluid communication with each other todirect a refrigerant fluid through the system to provide various HVACand/or APU operating modes. In particular, the power cycle loop sectionis configured for supporting a power generation mode for producingelectrical energy that may be stored in the battery packs to extend thevehicle's drivable range, or alternatively, that may be directed to thevehicle's electric motor to be used as an emergency range extender topropel the vehicle without the assistance of electrical energy from thebattery packs. The cabin heating cycle loop section is configured forsupporting a cabin heating mode for heating the passenger cabin of thebattery electric vehicle, and the cabin refrigeration cycle loop sectionis configured for supporting a cabin cooling mode for cooling thepassenger cabin. The cabin heating mode and/or the cabin cooling modemay be performed using electrical energy from the battery packs, oralternatively, may be performed in conjunction with the power generationmode without using electrical energy from the battery packs.

In an exemplary embodiment, the APU portion of the system includes aremovable auxiliary fuel cell and combustion unit and acompressor-expander train that is integrated with the HVAC portion ofthe system. The compressor-expander train has a reversingcompressor-expander, a high-pressure pump, a shaft and preferably amotor generator. The shaft operably couples the reversingcompressor-expander to the high-pressure pump and the motor generator.The high-pressure pump is disposed along the power cycle loop sectionand is configured to pressurize the refrigerant fluid to form ahigh-pressure refrigerant fluid. The auxiliary fuel cell and combustionunit contains a heat transfer fluid that is heated by combusting fuelthat is stored in the unit.

A heat exchanger is disposed along the power cycle loop section toreceive the high-pressure refrigerant fluid and is in fluidcommunication with the auxiliary fuel cell and combustion unit toreceive the heated transfer fluid. The heat exchanger transfers heatfrom the heated transfer fluid to the high-pressure refrigerant fluid toform a heated high-pressure refrigerant fluid. In an exemplaryembodiment, the heated high-pressure refrigerant fluid is fluidlycommunicated to and expanded by the reversing compressor-expander torotate the shaft to drive the high-pressure pump, and further, to drivethe motor generator to generate electrical energy for the powergeneration mode.

In another exemplary embodiment, the cabin heating mode is performedwithout using electrical energy from the vehicle's battery packs. Inparticular, the heated high-pressure refrigerant fluid from the heatexchanger is fluidly communicated to a cabin evaporator that is disposedalong the cabin heating cycle loop section. The cabin evaporatorextracts heat from the heated high-pressure refrigerant fluid to provideheat to the passenger cabin for the cabin heating mode.

In another exemplary embodiment, the cabin cooling mode is performedwithout using electrical energy from the vehicle's battery packs. Inparticular, the heated high-pressure refrigerant fluid from the heatexchanger is advanced through a linear solenoid injector AC pump, whichis in fluid communication with the cabin refrigeration cycle loopsection, causing a pressure drop across the cabin refrigeration cycleloop section. An expansion valve and a cabin condenser are disposedalong the cabin refrigeration cycle loop section, and the pressure dropcauses the refrigerant fluid in the cabin refrigeration cycle loopsection to advance through the expansion valve and the cabin condenser,expanding and cooling the refrigerant fluid to provide cooling to thepassenger cabin for the cabin cooling mode.

Thus, the HVAC-APU system is operational to perform the cabin heatingand/or cooling modes without using electrical energy from the vehicle'sbattery packs, such as, for example, when the energy charge runs out ofthe battery packs. Moreover, electrical energy produced during the powergeneration mode may be stored in the battery packs to extend thevehicle's drivable range to reduce range anxiety. Furthermore, energyproduced during the power generation mode may be directed to thevehicle's electric motor to be used as an emergency range extender topropel the vehicle to the nearest available power outlet if the batterypacks run out of energy without otherwise having the expense oftransporting the vehicle, e.g., via a flatbed truck or the alike.

Referring to FIG. 1, a schematic depiction of an exemplary embodiment ofthe HVAC-APU system 10 for a battery electric vehicle operating in acabin heating mode using battery stored electrical energy is provided.The system 10 includes a HVAC portion 12 and a partially integrated APUportion 14. The HVAC portion 12 is charged with refrigerant fluid and isconfigured to preferably operate under Rankine cycle conditions as iswell known in the art so that the refrigerant fluid is typicallyexpanded in a gas phase and pumped in a liquid phase. The APU portion 14includes an auxiliary fuel cell and combustion unit 15, and variousfunctioning elements integrated into the HVAC portion 12 along acompressor-expander train 16. The compressor-expander train 16 includesa reversing compressor-expander 18, a high-pressure pump 20, a motorgenerator 22 and a shaft 24 that operably couples the high-pressure pump20 and the motor generator 22 with the reversing compressor-expander 18.The various functioning elements of the APU portion 14 integrated alongthe compressor-expander train 16 include a fluid expander function ofthe reversing compressor-expander 18, the high-pressure pump 20 and theelectric generator function of the motor generator 22 as will beexplained in greater detail below.

As illustrated, the system 10 is operating in a cabin heating mode wherethe refrigerant fluid is advanced along a heating cycle loop 26indicated by lines 1, 2, 3, 4 and 5, and a cabin heating cycle loopsection 28 that are illustrated in bold. In particular, the motorgenerator 22 is driven by electrical energy provided from the batterypacks 30 to rotate the shaft 24 in a direction (e.g., compressiondirection) that drives the reversing compressor-expander 18 to compressthe refrigerant fluid that is provided from line 1 to form acompressed-heated refrigerant fluid. The compressed-heated refrigerantfluid is passed along line 2 to a mode selection valve 32 that directsthe compressed-heated refrigerant fluid to the cabin heating cycle loopsection 28 via line 3 and the mode selection valve 34.

Dispose along the cabin heating cycle loop section 28 are a cabinevaporator 36 and an expansion valve 38. As is known in the art, thecabin evaporator 36 extracts heat from the compressed-heated refrigerantfluid, and air passing over the cabin evaporator 36 carries at least aportion of the heat into the passenger cabin. The expansion valve 38expands the refrigerant fluid that is then fluidly communicated througha condenser 40, which is also referred to as the primary loop condenser,a recuperating heat exchanger 42, a liquid-gas separator 44, a bypassvalve 46, a linear solenoid injector AC pump 48 and the reversingcompressor-expander 18 via lines 4, 5 and 1, respectively, to completethe heating cycle loop 26.

Referring to FIG. 2, a schematic depiction of an exemplary embodiment ofthe HVAC-APU system 10 operating in a cabin cooling mode using batterystored electrical energy is provided. As illustrated, the refrigerantfluid is advanced along a refrigeration cycle loop 50 indicated by lines1, 2, 3, 6, 4 and 7, and a cabin refrigeration cycle loop section 52that are illustrated in bold. In particular, the motor generator 22 isdriven by electrical energy provided from the battery packs 30 to rotatethe shaft 24 in the compression direction, driving the reversingcompressor-expander 18 to compress the refrigerant fluid provided fromline 1 to form the compressed-heated refrigerant fluid. Thecompressed-heated refrigerant fluid is passed along line 2 to the modeselection valve 32 that directs the compressed-heated refrigerant fluidto the condenser 40 via mode selection valve 34 and line 6. Some of theheat is removed from the compressed-heated refrigerant fluid in thecondenser 40 and the recuperating heat exchanger 42 to form a compressedheat-depleted refrigerant fluid prior to being introduced to the cabinrefrigeration cycle loop section 52 via line 4 and the liquid-gasseparator 44. Dispose along the cabin refrigeration cycle loop section52 is an expansion valve 54 and a cabin condenser 56. As is well knownin the art, the expansion valve 54 and the cabin condenser 56 expand andcool the compressed heat-depleted refrigerant fluid, and air passingover the cabin condenser 56 is cooled and directed into the passengercabin for cooling. The expanded refrigerant fluid is passed from thecabin refrigeration cycle loop section 52 through the recuperating heatexchanger 42 to remove some of the heat from the counter flowingcompressed-heat depleted refrigerant fluid, and then is fluidlycommunicated to the reversing compressor-expander 18 via line 7, thelinear solenoid injector AC pump 48 and line 1, respectively, tocomplete the refrigeration cycle loop 50.

Referring to FIG. 3, a schematic depiction of an exemplary embodiment ofthe HVAC-APU system 10 for a battery electric vehicle operating in acabin heating mode and a power generation mode is provided. In thisembodiment, the HVAC portion 12 and the APU portion 14 cooperate togenerate electrical energy for the power generation mode. In particular,the auxiliary fuel cell and combustion unit 15 includes a fuel cell 58that is in fluid communication via line 62 with a combustor 60 toprovide fuel for combustion. The auxiliary fuel cell and combustion unit15 is removably connected to the system 10 by a plurality of quickconnects 64 that sealingly coupled together to complete the transferfluid loop 66. A circulating pump 68 is dispose along the transfer fluidloop 66 to circulate heat transfer fluid through the transfer fluid loop66. The combustor 60 generates heat by burning fuel from the fuel cell58 to heat the heat transfer fluid to a temperature of from preferablyabout 200 to about 300° C.

As illustrated, the system 10 is operating in both the cabin heatingmode and the power generation mode. For the power generation mode, therefrigerant fluid is advanced along a power cycle loop 70 indicated bylines 1, 8, 6, 4 and 9, and a power cycle loop section 72 that areillustrated in bold. Dispose along the power cycle loop section 72 arethe high pressure pump 20, an economizer heat exchanger 74 and arefrigerant-to-heat transfer fluid heat exchanger 76. The high pressurepump 20 pressurizes the refrigerant fluid to form a high-pressurerefrigerant fluid that is fluidly communicated to the economizer heatexchanger 74, which moderately increases the temperature of thehigh-pressure refrigerant fluid with the counter flowing refrigerantfluid in line 8 for overall system efficiency, before being introducedto the refrigerant-to-heat transfer fluid heat exchanger 76. Therefrigerant-to-heat transfer fluid heat exchanger 76, which is in fluidcommunication with the auxiliary fuel cell and combustion unit 15,transfers heat from the heated transfer fluid to the high-pressurerefrigerated fluid to form a heated high-pressure refrigerant fluid.

The reversing compressor-expander 18 is in fluid communication with thepower cycle loop section 72 via line 9. The reversingcompressor-expander 18 receives and expands the heated high-pressurerefrigerant fluid to rotate the shaft 24 in a power generation direction(e.g., opposite the compression direction), driving the high-pressureliquid pump 20, the circulating pump 68 and a motor generator 22. Themotor generator 22 generates electrical energy in response to beingdriven by the shaft rotating in the power generation direction. Thegenerated electrical energy, for example, may be stored in the batterypacks 30 to extend the vehicle's drivable range, or alternatively, maybe directed to the vehicle's electric motor 78 to be used as anemergency range extender to propel the vehicle without the assistance ofelectrical energy from the battery packs 30.

For the cabin heating mode performed in conjunction with the powergeneration mode, the mode selection valves 32 and 34 direct a portion ofthe heated high-pressure refrigerant fluid from the refrigerant-to-heattransfer fluid heat exchanger 76 to the cabin heating cycle loop section28 via lines 2 and 3. The cabin evaporator 36 extracts heat from theheated high-pressure refrigerant fluid, and air passing over the cabinevaporator 36 carries some of the heat into the passenger cabin. Theexpansion valve 38 expands refrigerant fluid that is then fluidlycommunicated to the power cycle loop 70.

Referring to FIG. 4, a schematic depiction of an exemplary embodiment ofthe HVAC-APU system 10 operating in a cabin cooling mode and a powergeneration mode is provided. The HVAC portion 12 and the APU portion 14cooperate to generate electrical energy for the power generation mode asdiscussed in the foregoing paragraphs in relation to FIG. 3.

For the cabin cooling mode performed in conjunction with the powergeneration mode, the mode selection valves 32 and 34 are set so as tonot direct the refrigerant fluid through the cabin heating cycle loopsection 28. The linear solenoid ejector AC pump 48 is in fluidcommunication with the cabin refrigeration cycle loop section 52 and therefrigerant-to-heat transfer fluid heat exchanger 76 to receive two feedstreams including the refrigerant fluid from the cabin refrigerationcycle loop section 52 and the heated high-pressure refrigerant fluid vialines 7 and 11, respectively. With the two feed streams, the linearsolenoid ejector AC pump 48 functions as a thermal compressor having theheated high-pressure refrigerant fluid as a high energy motive fluidrunning through an acceleration nozzle (e.g., a venturi effect producedfrom a narrow to large diffusion nozzle) at supersonic speed such thatthe slower adjacent refrigerant fluid from the cabin refrigeration cycleloop section 52 is sucked in and mixes with the heated high-pressurerefrigerant fluid to produce a pressure drop across line 7 and the cabinrefrigeration cycle loop section 52. The refrigerant fluid mixtureexpands and exits the linear solenoid ejector AC pump 48 at a relativelylow velocity and high pressure. The exiting refrigerant fluid mixture iscombined with the refrigerant fluid exiting the reversingcompressor-expander 18 at line 8. The linear solenoid ejector AC pump 48may be modulated so that the exiting refrigerant fluid mixture is atabout the same pressure and temperature, e.g., about 100 to about 120°C., as the refrigerant fluid stream from the reversingcompressor-expander 18 along line 1. The combined refrigerant fluidmixture is then fluidly communicated to the cabin refrigeration cycleloop section 52 through the economizer heat exchanger 74, line 6, thecondenser 40, the recuperating heat exchanger 42, line 4 and theliquid-gas separator 44.

The pressure drop across the cabin refrigeration cycle loop section 52accelerates the refrigerant fluid, which is at a relatively highpressure, through the expansion valve 54 and the cabin condenser 56 toexpand and cool the refrigerant fluid. Air passing over cabin condenser56 is cooled by the cooled refrigerant fluid and is directed into thepassenger cabin for cooling.

Referring to FIG. 5, a schematic depiction of an exemplary embodiment ofthe HVAC-APU system 10 operating in a cabin demisting mode and a powergeneration mode is provided. The HVAC portion 12 and the APU portion 14cooperate to generate electrical energy for the power generation mode asdiscussed in the foregoing paragraphs in relation to FIG. 3.

For the cabin demisting mode performed in conjunction with the powergeneration mode, both the cabin heating mode and the cabin cooling modeas discussed in relation to FIGS. 3 and 4 are performedcontemporaneously by directing fluid communication between the powercycle loop section 72, the cabin heating cycle loop section 28 and thecabin refrigeration cycle loop section 52 such that the cabin evaporator36 is heated by the heated high-pressure refrigerant fluid, and therelatively high pressure refrigerant fluid from the linear solenoidejector AC pump 48 and the reversing compressor-expander 18 isaccelerated through the expansion valve 54 and the cabin condenser 56 tocool the cabin condenser 56. An air stream is directed over the cooledcabin condenser 56, which cools and dehumidifies the air, and issubsequently directed over the heated cabin evaporator 36, which returnsheat back into the cool-dried air, to form a warm-dry air streamdirected towards the passenger cabin for demisting.

Accordingly, HVAC-APU systems for battery electric vehicles have beendescribed. The various embodiments comprise a power cycle loop section,a cabin heating cycle loop section, and a cabin refrigeration cycle loopsection that are in selective fluid communication with each other todirect a refrigerant fluid through the system to provide various HVACand/or APU operating modes. In particular, the power cycle loop sectionis configured for supporting a power generation mode for producingelectrical energy that may be stored in the battery packs to extend thevehicle's drivable range, or alternatively, that may be directed to thevehicle's electric motor to be used as an emergency range extender topropel the vehicle without the assistance of electrical energy from thebattery packs. The cabin heating cycle loop section is configured forsupporting a cabin heating mode for heating the passenger cabin of thebattery electric vehicle, and the cabin refrigeration cycle loop sectionis configured for supporting a cabin cooling mode for cooling thepassenger cabin. The cabin heating mode and/or the cabin cooling modemay be performed using electrical energy from the battery packs, oralternatively, may be performed in conjunction with the power generationmode without using electrical energy from the battery packs. Thus, theHVAC-APU system is operational to perform the cabin heating and/orcooling modes without using electrical energy from the vehicle's batterypacks, such as, for example, when the energy charge runs out of thebattery packs. Moreover, electrical energy produced during the powergeneration mode may be stored in the battery packs to extend thevehicle's drivable range to reduce range anxiety. Furthermore, energyproduced during the power generation mode may be directed to thevehicle's electric motor to be used as an emergency range extender topropel the vehicle to the nearest available power outlet if the batterypacks run out of energy without otherwise having the expense oftransporting the vehicle, e.g., via a flatbed truck or the alike.

While at least one exemplary embodiment has been presented in theforegoing Detailed Description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or exemplary embodiments are only examples, and arenot intended to limit the scope, applicability, or configuration in anyway. Rather, the foregoing Detailed Description will provide thoseskilled in the art with a convenient road map for implementing anexemplary embodiment of the invention, it being understood that variouschanges may be made in the function and arrangement of elementsdescribed in an exemplary embodiment without departing from the scope ofas set forth in the appended Claims and their legal equivalents.

1. A HVAC-APU system for an electric vehicle, the system comprising: arefrigerant fluid; a power cycle loop section configured to advance therefrigerant fluid; a cabin heating cycle loop section in selective fluidcommunication with the power cycle loop section and configured toadvance the refrigerant fluid; a cabin refrigeration cycle loop sectionin selective fluid communication with the power cycle loop section andthe cabin heating cycle loop section and configured to advance therefrigerant fluid with the power cycle loop section and the cabinheating cycle loop section; a compressor-expander train comprising areversing compressor-expander, a high-pressure pump and a shaft thatoperably couples the reversing compressor-expander with thehigh-pressure pump, the high-pressure pump disposed along the powercycle loop section and configured to pressurize the refrigerant fluid toform a high-pressure refrigerant fluid; an auxiliary fuel cell andcombustion unit containing a heat transfer fluid and configured to heatthe heat transfer fluid to form a heated transfer fluid; and a heatexchanger disposed along the power cycle loop section to receive thehigh-pressure refrigerant fluid and is in fluid communication with theauxiliary fuel cell and combustion unit to receive the heated transferfluid, the heat exchanger configured to transfer heat from the heatedtransfer fluid to the high-pressure refrigerant fluid to form a heatedhigh-pressure refrigerant fluid, wherein the reversingcompressor-expander is in selective fluid communication with the heatexchanger to receive the heated high-pressure refrigerant fluid and isconfigured to expand the heated high-pressure refrigerant fluid torotate the shaft in a first direction to drive the high-pressure pump.2. The system according the claim 1, wherein the compressor-expandertrain further comprises a motor generator operably coupled to thereversing compressor-expander by the shaft, and wherein the motorgenerator is configured to be driven by the shaft rotating in the firstdirection to generate electrical energy to define a power generationmode.
 3. The system according to claim 2, further comprising a batteryconfigured to store the electrical energy generated during the powergeneration mode.
 4. The system according to claim 2, further comprisingan electric motor configured to operably drive the electric vehicleduring the power generation mode with the electrical energy.
 5. Thesystem according to claim 2, further comprising a cabin evaporatordisposed along the cabin heating cycle loop section that is in selectivefluid communication with the heat exchanger and configured to receivethe heated high-pressure refrigerant fluid, the cabin evaporator furtherconfigured to extract heat from the heated high-pressure refrigerantfluid for heating a passenger cabin of the electric vehicle.
 6. Thesystem according to claim 5, wherein the system is operable in a cabinheating mode and the power generation mode when the power cycle loopsection and the cabin heating cycle loop section are in fluidcommunication.
 7. The system according to claim 5, further comprising: aprimary loop condenser in fluid communication with the reversingcompressor-expander and configured to receive the refrigerant fluid; anexpansion valve disposed along the cabin refrigeration cycle loopsection that is in selective fluid communication with the primary loopcondenser to receive the refrigerant fluid; a cabin condenser disposedalong the cabin refrigeration cycle loop section that is in selectivefluid communication with the primary loop condenser to receive therefrigerant fluid, the expansion valve and the cabin condensercooperatively configured to expand and cool the refrigerant fluid forcooling the passenger cabin; and a linear solenoid ejector AC pump inselective fluid communication with the heat exchanger and the cabinrefrigeration cycle loop section and configured to receive the heatedhigh-pressure refrigerant fluid and the refrigerant fluid, the linearsolenoid ejector AC pump further configured to advance the heatedhigh-pressure refrigerant fluid and the refrigerant fluid producing apressure drop across the cabin refrigeration cycle loop section toadvance the refrigerant fluid through the expansion valve and the cabincondenser.
 8. The system according to claim 7, wherein the system isoperable in a cabin cooling mode and the power generation mode when thepower cycle loop section and the cabin refrigeration cycle loop sectionare in fluid communication.
 9. The system according to claim 7, whereinthe system is operable in a cabin demisting mode and the powergeneration mode when the power cycle loop section, the cabin heatingcycle loop section and the cabin refrigeration cycle loop section are influid communication.
 10. The system according to claim 7, wherein themotor generator is configured to be driven by battery stored electricalenergy to rotate the shaft in a second direction in a non-powergeneration mode when the reversing compressor-expander is not in fluidcommunication with the heat exchanger of the power cycle loop section,and wherein the reversing compressor-expander is configured to compressthe refrigerant fluid when rotated by the shaft in the second directionto form a compressed refrigerant fluid.
 11. The system according toclaim 10, wherein the cabin evaporator is configured to extract heatfrom the compressed refrigerant fluid for heating the passenger cabinwhen the cabin evaporator of the cabin heating cycle loop section is notin fluid communication with the heat exchanger of the power cycle loopsection but is in fluid communication with the reversingcompressor-expander to receive the compressed refrigerant fluid.
 12. Thesystem according to claim 10, wherein the expansion valve and the cabincondenser are cooperatively configured to expand and cool the compressedrefrigerant fluid for cooling the passenger cabin when the linearsolenoid ejector AC pump is not in fluid communication with the heatexchanger of the power cycle loop section but the primary loop condenseris in fluid communication with the reversing compressor-expander toreceive the compressed refrigerant fluid.
 13. The system according toclaim 1, further comprising a circulation pump in fluid communicationwith the heat transfer fluid and operably coupled to the shaft toadvance the heated transfer fluid from the auxiliary fuel cell andcombustion unit to the heat exchanger in response to the shaft rotatingin the first direction.
 14. The system according to claim 1, wherein theauxiliary fuel cell and combustion unit is removably connected to thesystem.
 15. A HVAC-APU system for a battery electric vehicle that has apassenger cabin, the HVAC-APU system configured to receive an auxiliaryfuel cell and combustion unit that contains a heat transfer fluid andwhich is operable to heat the heat transfer fluid to form a heatedtransfer fluid, the system comprising: a refrigerant fluid; a powercycle loop section, a cabin heating cycle loop section, and a cabinrefrigeration cycle loop section that are in selective fluidcommunication with each other to advance the refrigerant fluid throughthe system to provide various operating modes; a compressor-expandertrain comprising a reversing compressor-expander, a high-pressure pumpand a shaft that operably couples the reversing compressor-expander withthe high-pressure pump, the high-pressure pump disposed along the powercycle loop section and configured to pressurize the refrigerant fluid toform a high-pressure refrigerant fluid; and a heat exchanger disposedalong the power cycle loop section to receive the high-pressurerefrigerant fluid, the heat exchanger configured for fluid communicationwith the auxiliary fuel cell and combustion unit to receive the heatedtransfer fluid and to transfer heat from the heated transfer fluid tothe high-pressure refrigerant fluid to form a heated high-pressurerefrigerant fluid, wherein the reversing compressor-expander is inselective fluid communication with the heat exchanger to receive theheated high-pressure refrigerant fluid and is configured to expand theheated high-pressure refrigerant fluid to rotate the shaft in a firstdirection to drive the high-pressure pump.
 16. The system according toclaim 15, wherein the compressor-expander train further comprises amotor generator operably coupled to the reversing compressor-expander bythe shaft, and wherein the motor generator is configured to be driven bythe shaft rotating in the first direction to generate electrical energyto define a power generation mode.
 17. The system according to claim 15,further comprising a cabin evaporator disposed along the cabin heatingcycle loop section that is in selective fluid communication with theheat exchanger to receive the heated high-pressure refrigerant fluid,the cabin evaporator configured to extract heat from the heatedhigh-pressure refrigerant fluid for heating the passenger cabin.
 18. Thesystem according to claim 15, further comprising: a primary loopcondenser in fluid communication with the reversing compressor-expanderto receive the refrigerant fluid; an expansion valve and a cabincondenser that are disposed along the cabin refrigeration cycle loopsection that is in selective fluid communication with the primary loopcondenser to receive the refrigerant fluid, the expansion valve and thecabin condenser cooperatively configured to expand and cool therefrigerant fluid for cooling the passenger cabin; and a linear solenoidejector AC pump in selective fluid communication with the heat exchangerand the cabin refrigeration cycle loop section to receive the heatedhigh-pressure refrigerant fluid and the refrigerant fluid, respectively,the linear solenoid ejector AC pump configured to advance the heatedhigh-pressure refrigerant fluid and the refrigerant fluid therethroughso as to cause a pressure drop across the cabin refrigeration cycle loopsection to advance the refrigerant fluid through the expansion valve andthe cabin condenser.
 19. The system according to claim 15, furthercomprising a circulation pump operably coupled to the shaft andconfigured for fluid communication with the heat transfer fluid toadvance the heated transfer fluid from the auxiliary fuel cell andcombustion unit to the heat exchanger in response to the shaft rotatingin the first direction.
 20. The system according to claim 15, furthercomprising a plurality of quick connects for removably connecting theauxiliary fuel cell and combustion unit to the system.